Supercapacitors (SCs) are crucial for high-performance energy storage, offering high power density, swift charge-discharge rates, and durability. The enhancement of their performance hinges on the development of advanced electrode materials. This study presents an innovative method involving polyacrylonitrile (PAN) nanofibers adorned with manganese dioxide (MnO2) nanoparticles (NPs), created through electrospinning and subsequent thermal treatment. This synergy exploits the extensive surface area and electrical conductivity of PAN nanofibers along with the substantial capacitance of MnO2. The MnO2-coated PAN nanofibers reached an impressive specific capacitance of 247 F g-1 at a scan rate of 10 mVs-1, markedly boosting the efficacy of all-solid-state asymmetric SCs. The SCs, incorporating a polyvinyl alcohol (PVA)/potassium hydroxide (KOH) gel electrolyte, exhibited an energy density of 8.2 Wh kg-1 at a power density of 700 W kg-1, preserving 80.4% of their original capacitance after 5000 cycles. This research is pioneering in combining MnO2 with PAN nanofibers, marking a significant leap forward in supercapacitor technology with enhanced energy storage capacity and prolonged stability. These findings underscore the promise of these composite materials in future energy storage solutions.